When producing a well, hydrocarbons or other fluids to be recovered are provided with a natural lift due to dissolved gasses within the fluid, which facilitates recovery of the fluid. However, during production, this natural lift diminishes and eventually ceases, requiring other methods to be undertaken to continue producing from a reservoir.
To simulate the lifting effect of natural gasses, one or more compressed gasses, known as lift gasses, can be injected into a well to reduce the density of the hydrocarbon fluid, or other fluid to be recovered. Typically, a substantially non-combustible, non-condensible, inert gas that will not react with, corrode, or degrade well equipment or compounds within the well, and will not support significant microbial growth, such as nitrogen, is utilized.
The equipment required to generate, compress, inject, and recover lift gas, is expensive and bulky, which can be a significant drawback when space on or proximate to a well is limited. Further, the fuel reservoirs or other power sources necessary to utilize such equipment are also expensive and cumbersome.
It is often economically disadvantageous to produce a well using a lift gas. Frequently, the value of the fuel required to generate and compress the lift gas exceeds that of the product recovered from the well. A significant quantity of energy is required to compress enough nitrogen, or another gas, to extract product from a well. The energy costs, coupled with the costs required to transport fuel to the well to power the lift gas operation, can cause a production operation to become prohibitively expensive.
A separator can be used to separate lift gas from the extracted product, enabling the lift gas to be recycled and recompressed. However, even when recycled lift gas is used, a significant percent of the initial lift gas, such as fifteen percent, or more, is normally lost and must be regenerated, and a significant amount of recompression of the recycled gas is usually required.
When producing a hydrocarbon well using a lift gas, it is common for natural gas from the well to become mixed with the lift gas, and remain entrained with the lift gas after the produced fluid hydrocarbons have been separated.
A need exists for a system and method that can selectively separate the natural gas from the lift gas, and depending on the economic viability of each alternative, can selectively: 1) recycle and compress the gas, thereby conserving the costs associated with the production and compression of lift gas; 2) collect the natural gas for sale; or 3) use the natural gas to provide power for compressing the lift gas, thereby conserving costs related to fuel use, storage, and transport.
A further need exists for a system and method that can seamlessly and intelligently alternate between each aforementioned alternative, depending on changes in both the practical and economic viability of each alternative.
The present embodiments meet these needs.